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A3 8l 2003 rear amp too weak. Can I swap it with minimum rewiring. Ok leading 12v fee

Discussion in 'In-Car Entertainment' started by _Alex_D_, Sep 3, 2013.

  1. _Alex_D_
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    _Alex_D_ Member

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    [Sep 3, 2013]
    Want to improve sound in rear. Not enough bass as amp is week. Go alpine Ida 311 Hu powering front. Heard amping rear would improve things on a budget. Then at later date can get new sub box and sub. Was thinking of four channel amp but can I use existing wires for speakers and ignition wire etc. Then just lead a new 12v from battery.

    Not looking for mega power. Like a 150 watt amp just to balance front and rear out as Hu is 45 per channel.


    Other than that are the later models amps better. I know in 12 amp is bang olfuson. Could do a swap or maybe just with 8v A3
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    [Dec 27, 2014]

  3. _Alex_D_
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    _Alex_D_ Member

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    [Sep 11, 2013]
    Anyone? Does anyone know anywhere that will fit a amp and sub for me then. Ilkeston area (notss/derby) not Halfords cause iI don't trust them
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  4. A4 stu
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    A4 stu Member

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    [Sep 14, 2013]
    When I replaced the HU in my A4 B5 model I had the same problem - because the new HU provided the fronts with more power than the rear amp gave the rears the sound was out of balance.

    I found that if I fed the factory amp, not with the RCA rear output from the HU but if I fed it from the rear HU speaker output, after it had gone though a high to low convertor, it sounded much better.

    Basically this gave the amp a higher voltage input to work with, ie it gave it more to amplify.

    The balance was restored and it did sound more powerful albeit just because it went louder.

    Assuming your not feeding more than a genuine 50w from an amp then I would be happy to use the factory speaker wire and remote on lead but you should definitely improve the power supply cable and match it with a same sized earth for the amp.

    Stu.
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  5. _Alex_D_
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    _Alex_D_ Member

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    [Sep 14, 2013]
    I've just finished feeding speaker wire from rear output of hu straight to sub speaker. Giving 50w to sub instead of 20w. Sounds loads better. Rear speakers are still quiet but don't want to move sounds to rear to much.
    #4
  6. dualmono21
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    dualmono21 Well-Known Member

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    [Sep 15, 2013]
    just to check

    have you wired the rear speaker output of the headunit directly to the subwoofer speaker
    if so take it off immediatedly you will damage your headunit as the outputs are non bridgable

    what stu was saying it
    use the rear speaker outputs of the headunit and a speaker to line level convertor connected to the amplifier
    #5
  7. _Alex_D_
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    _Alex_D_ Member

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    [Sep 15, 2013]
    Dam really. It sounded so good too. Didn't think they were bridged as sub is dual voice
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  8. _Alex_D_
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    _Alex_D_ Member

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    [Sep 15, 2013]
    I don't understand how that's bridge. Connected left output to one voice coil and right to other. Should I just disconnect one output. Didn't want to connect like stuffsaid bbecause that uses audi amp which is weak. This way get more power to sub
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  9. dualmono21
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    dualmono21 Well-Known Member

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    [Sep 15, 2013]
    i assumed that the sub was single voice coil and that the outputs had been bridged to power the sub

    however it matters not
    you cannot run a subwoofer off the rear outputs of a headunit
    if you try and do so you will blow the headunit up and will then have no sound whatsoever

    if you have a dual voice coil sub you need an amplifier capable of driving it properly
    #8
  10. _Alex_D_
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    _Alex_D_ Member

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    [Sep 23, 2013]
    It's only a 50w sub so why can't I use 45wpc hu. Audi thing is only 20w
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  11. dualmono21
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    dualmono21 Well-Known Member

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    [Sep 23, 2013]
    dont believe the advertising

    under normal conditions all headunits can make an absoloubt maximum power limit of 18 watts rms
    this is because the chip which is used to amplifiy the signal cannot dissipate heat efficiently so is limited to the power it can put out

    the audi seperate amplifier will be far superior to a single chip which is in a headunit
    if you want to do it properly replace the amplifier with a proper one and drive the entire system off this
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  12. _Alex_D_
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    _Alex_D_ Member

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    [Sep 24, 2013]
    Oh Ok. Fair point about Hu amps. I know none of them would put at 50w like they claim but my main reason for Wiring this way was to I could give more power to sub than rear speakers. I didn't want to move soundstage to rear to increase bass.
    It now sounds better. Not great, I've had 300w amps just to power sub in boot and good speakers but I'm older now and ddon't h
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  13. _Alex_D_
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    _Alex_D_ Member

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    [Sep 24, 2013]
    Have 300quid spare to spend on amp box, amp and jl speaker
    #12
  14. dualmono21
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    dualmono21 Well-Known Member

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    [Sep 24, 2013]
    ebay is your friend !!!
    if you know what to look for you can spend relatively nothing and end up with a cracking system
    #13
  15. _Alex_D_
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    _Alex_D_ Member

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    [Sep 24, 2013]
    Go on then what do I want? 6.5 inch sub and 4 way amp. Seen sub enclosure for 50.
    #14
  16. _Alex_D_
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    _Alex_D_ Member

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    [Sep 24, 2013]
    I have all wires from old sub
    #15
  17. cooper86
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    cooper86 Member

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    [Sep 24, 2013]
    i'm currently trying to sell a vibe slick 12" sub and 600w ground zero amp if your interested,no use to me as i need boot space for pushchair :ermm:
    #16
  18. _Alex_D_
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    _Alex_D_ Member

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    [Sep 24, 2013]
    Barry a long way from me
    #17
  19. dualmono21
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    dualmono21 Well-Known Member

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    [Sep 25, 2013]
    #18

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